The Oakley SI M Frame surpasses ANSI Z87.1 Industrial Standards for high-mass and high-velocity impact protection Incorporating HIGH DEFINITION OPTICS (HDO) technology, lens geometry comes in five interchangeable lens shapes. All lenses are made of pure Plutonite, a proprietary material that offers the highest level of optical clarity available in eyewear. You get razor-sharp clarity at all angles of view, which maximizes peripheral vision and protection against sun, wind and side impact.